Various methods are known for covering side walls of electrolytic cells used in the amalgam process, which are generally made of metal. A non-detachable covering of rubber (synthetic or natural rubber) is generally applied.
The non-detachable rubber covering is in other cases provided with an additionally bonded sheet of for example ethylene-propylene-terpolymer (see for example U.S. Pat. No. 3 450 621).
On rubber-covered side pieces dioxin-containing and furan-containing reaction products are in certain circumstances formed by reaction with chlorine gas. These are undesirable by-products on account of their toxicity, which have to be removed at great expense. When a side piece of an electrolytic apparatus is to be re-covered, the existing rubber covering must first of all be removed. This is normally achieved by cooling the rubber covering to a very low temperature, whereupon the covering becomes brittle and can then be mechanically removed, for example by chiselling off the adhering rubber residues.
A side piece covering comprising a combination of rubber and an additional polymer layer as described above is complicated to produce and is also expensive. If the rubber covering is damaged moist chlorine can come into contact with the surface of the side pieces, which are normally made of steel, and cause serious corrosion of the steel part. A proper repair welding of the bonded polymer covering is not possible in practice.